You do not say how old your plant is…but you need to give it about two years (tow growing seasons) to become established. Old plants become spindly and thin when they are overcrowded; they would need to be divided and replanted (whereupon the two-year establishment cycle would start again). It’s also possible that your plant lacks vigor due to poor soil: Rhubarb is a heavy feeder: it loves organic matter such as aged manure and/or rich compost. It should get full sun and regular watering. Anything here sound like a fit?
You do not say how old your plant is…but you need to give it about two years (tow growing seasons) to become established. Old plants become spindly and thin when they are overcrowded; they would need to be divided and replanted (whereupon the two-year establishment cycle would start again). It’s also possible that your plant lacks vigor due to poor soil: Rhubarb is a heavy feeder: it loves organic matter such as aged manure and/or rich compost. It should get full sun and regular watering. Anything here sound like a fit?